Article Tools

Abstract

Coherent optical orthogonal frequency division multiplexing (CO-OFDM)
systems have inferior nonlinear performance due to their high peak to average
power ratio (PAPR) characteristics. In order to mitigate fiber nonlinearities
for the CO-OFDM systems, we propose a novel discrete Fourier transform (DFT)-precoded
coherent optical OFDM combined with a Hermitian symmetry (DFT-precoded HS
CO-OFDM) system, which is a combination of the DFT-spread OFDM and the Hermitian
symmetry of the DFT. Furthermore, the proposed system can be easily implemented
by using a fast Fourier transform (FFT) algorithm. Because the proposed system
has a lower PAPR than the conventional CO-OFDM system, the DFT-precoded HS
CO-OFDM system provides superior nonlinear tolerance. Moreover, the proposed
system is superior to the conventional DFT-spread coherent optical OFDM (DFT-spread
CO-OFDM) system in terms of maintaining low PAPR in optical fiber transmission.
The low PAPR in the proposed scheme is suitable for long-haul optical transmission
systems, compared with the conventional DFT-spread CO-OFDM. For the DFT-precoded
HS OFDM system, we have developed a theoretical framework illustrating the
principles of the proposed system. The numerical results show that the DFT-precoded
HS CO-OFDM system outperforms the conventional CO-OFDM by 5.4% EVM performance
after 1200-km transmission and the conventional DFT-spread CO-OFDM by 4.5%
EVM performance after 2800-km transmission at a fiber launch power of -2 dBm.

Cited By

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.